Belt-tightener.



No. 888,031. PATENTED MAY 19, 1908. W. B. PARRISH.

BELT TIGHTENER.

APPLIGATION FILED ooT.18. 1901.

of which the ollowing WASHINGTON B. PARRISH, OF KARA, VIRGINIA.

BELT-TIGHTENER.

Specification of Letters Patent. Y A

Patented May 19, 1908.

Application led October 18, 1901. Serial No. 397,993.

To all whom it may concern:

Be it known that I, WASHINGTON B. PAE- RIsH, citizen ofthe United States, residin at Kara, in the county of Lunenburg and State of Virginia, have invented certain new and useful Im. rovements inBelt-Tighteners,

iP is a specification.

This invention relates to means for maintaining drive belts under proper tension and obviating injury thereto by contraction in damp weather and preventing sli ping of the belt due to expansion thereof in ry weather.

The invention provides an ap liance which ma be mounted upon the sha t of the drive pul ey so as to be supported thereby and held 1n relatively fixed position with reference to the ulley and the belt to be tightened.

Tlie invention consists of a sup orting structure, a frame having adjustab e connection with the supporting structure, ulleys for engaging with the runs of the be t to be tightened, and adjusting means for moving said pulleys either to vary the distance between them or to cause one pulley to incline more or less with reference to the other, as maybe desired to meet existing conditions and t0 cause the drive belt to adhere to the drive pulley to prevent displacement therefrom.

For a full understandin and the merits thereof ang also to acquire a knowledge of the details of construction and the means for effecting the result, reference is to be had to the following description and accom anying drawings.

Whi e the invention may be adapted to different forms and conditions by changes in the structure and minor details without deof the invention partin from the spirit or essential features thereo still the preferred embodiment is shown in the accompanying drawings, in which:

Figure 1 is a perspective view of a belt tightener embodying the invention. Fig. 2 is a front view of the belt tightener, the side frames of the supporting structure being in section and parts of the pulley frame being broken away. Fig. 3 is a horizontal section on the line xof Fig. 2. Fig. 4 is a sectional view of a side portion of the belt tightener similar to Fig. 3, showing the parts on a larger scale.

Corresponding and like parts are referred to in the followin in all the views oig the drawings by the same reference characters.

description and indicated` The belt or drive ulley l may be of any design and mounted upon its supporting shaft 2 in any manner. The drive belt 3 may be such as usually em loyed for trans mitting powerfrom one pulley t0 another The belt tightenerv comprises a supporting structure consisting of side frames 4, a pulley frame 5, belt engaging pulleys 6 and mountings and adjusting means for said pulleys 6. The side frames 4 are of triangular form, the inclined bars being slotted to receive the bolts or fastenings by means of which the pulley frame is adjustably connected thereto, said pulley frame also serving to connect the frames 4 and in conjunction therewith provide a substantial framework for supporting the pulleys 6 and the mountings and adjusting means therefor. The frames 4 are provided with bearings both at their apexes and bases to receive the shaft 2 as may be found most advantageous or convenient, said bearings embodying removable caps and boXes of Babbitt metal. The frames 4 are preferably of cast metal, although they may be constructed of any suitable material so as to provide a substantial construction.

The pulley frame 5 is of rectangular formation and consists of side bars 7 and end bars 8, the side bars having slots 9 to receive the bolts or fastenings 11 by means of which the frames 4 and 5 are secured in any adjusted position, said bolts or fastenings 11 passing through the slots 12 provided in the inclined bars of the frames 4. The belt engaging pulleys 6 are mounted at their ends 1n bearlngs 13 which are adjustable on the bars 7 of the pulley frame to admit of varying the distance between said pulleys and to adjust their relative inclination. The bearings 13 are slidable on the bars 7 and are held thereto against displacement in any manner. The bars 7 are of wedge form in cross section and the bearings 13 have openings 14 of wedge form to fit the bar 7 so as to hold the bearings thereto and yet admit oftheir free movement. Set screws 15 are mounted in the end bars 8 of the ulley frame and in inner proj ections 16 and) have screw thread connection with the respective bearin s 13 so that rotation of said set screws wil effect movement of the bearings 13 along the side bars 7 of the pulley frame. The set screws may be turned 1n any manner, as by means of cranks 17 iitted to the projecting ends thereof. To x the position of the set screws, after the bearings 13 have been moved to the desired posiadapted to engage formed in the bearing ceive the ball 19, the

the universal joint between the mounts of the tion, suitable means are provided, and as l shown consist of thumb screws 18 threaded into openings of the inner projections 16 and at their inner ends with the set screws 15. It is desirable under some circumstances to adjust one bearing 13 to a greater or less extent than the oppositel cooperatinfr bearing,4 and in order to revent binding between the journals of the elt engaging pulleys 6 and the bearings 13, a'universal joint is interposed between said journals and bearings. This joint consists of a ball 19 and a socket 20, the latkxr being 13 and of a s ze to reatter in turn having an opening to receive the journal 21 of the pulley 6. In the event of the bearin s of a pulley 6 being adjusted unevenly, the balls 19 move in the sockets 20 and adapt themselves to the position of the said pulley 6, thereby reventing any possible binding between the journals 21 of the pulley 6'and the parts in which said journals are mounted.

The lmain supporting frame comprising the parts 4, is mounted upon the shaft 2 receiving the pulleyl 1 around which the belt 3 passes and to W ich .the tightener is to be applied, the shaft 2 being mounted in the bearings of the frames 4 either at the angles thereof or the bearings provided at the bases according to convenience and as may be found .to give the best results. The runs of the belt 3 pass between the pulleys 6 and by o erating the set screws 15, said pulleys may be advanced or separated to subject the drive belt to the proper tension. When the belt tends to contract, as in damp weather, the set screws 15 may be turned to separate the ulley 6, thereby easing the tension on the rive belt so as to prevent abnormal strain thereon. On the other hand should the drive belt lengthen, as in dry weather or from use, the tension thereon may be increased by turning the set screws 15 to advance the pulleys 6. Should it be required to incline one or both runs of the drive belt to prevent the same slipping from the drive pu ley, either one of the set screws 15 ma be movedto throw the pulleys 6 at the desired relative inclination,

pulleys 6 and their bearings 13 Ycom ensating for the change in position ofthe pu eys so as to prevent any binding between the journals 21 of the belt engagin pulleys 6 and the mounts of balls 19 in wiich the journals 21 are fitted. v

The set screws 15 have their end portions oppositely threaded and are mounted in the bearings 16 and in the end bars 8 so as to be held against longitudinal movement. The

inner ends of the set screws 18 `may enter grooves mountedl inthe bearings 16 soas to prevent lon 'tudinal movement of said set screws. By aving the 'end portions ofthe set screws oppositel threaded rotation of said set screws 'a out their axes will effect simultaneous movement of the bearings 13 either towards or 'from one another.

Having thus described the invention, what is claimed as new is:

l1. In a belt tightener, the combination of a frame coin rising oppositely inclined bars, a ,pulley at t e converging ends of said bars, a

pulley frame having adjustable connection with the aforesaid oppositely inclined bars, spaced pulle s mounted upon Y the pulley frame and a apted to engage o posite runs of a belt passin around thea ley, and means Ier varying the distance between said belt engaging pulleys.

2. In combination, a pulley frame comprising oppositely dis osed bars of wedge form in cross section, earings having openings of wedge form to receive said bars and forman interlocking joint therewith to revent displacement, ulle mounts fitte to said bearings and'se f-adjustable with reference thereto, belt engaging pulleys journaled in said mounts, and means for adjusting the bearings to vary the distance between said.

belt engaging pulleys.

3. In a belt tightener, the combination of a frame having inner bearings intermediate the extremities of opposite side bars and having the latter of wedge form in cross section, bearings having openings of wedge form to receive and interlock with the said wedge bars of the frame, set screws mounted in said inner bearings and in opposite bars of the frame and having screw thread connection with the aforesaid bearings to move the latter, pulley mounts carried by said bearings and self-adjustablel with reference thereto, and belt engaging pulleys journaled in said pulley mounts.

4. A belt tightener comprising supporting frames ada ted to be' mounted upon the shaft of a belt pu ley, a pulley frame having adjustable connection with'said su porting frames and forming a tie therefor, be t enig-raging pulleys su ported upon the pulley ame, and means or relatively adjusting saidl belt engaging pulleys to vary the distance between themor to change their relative inclination.

WASHINGTON riiuiisii. [n 8.]

Witnesses:

V. B. HILLYARD, W. N. WooDsoN.

in the portions of theset screws 15` l oresaid vpul- 

